Chemistry is the science of the structure and interactions of matter. The INCORRECT alternative is: D) All living and nonliving things consist of matter, which is anything that occupies space and has mass. Mass is the amount of matter in any object, which does not change. Weight, the force of gravity acting on matter, does change. When objects are farther from Earth, the pull of gravity is strong; this is why the weight of an astronaut is close to zero in outer space.
States of Matter
The substance that constitutes everything in the universe is known as matter. Matter comprises atoms which in turn are composed of electrons, protons, and neutrons. Different atoms combine together to give rise to molecules that act as a foundation for all kinds of substances. There are five states of matter based on their energies of attraction, namely solid, liquid, gases, plasma, and BEC (Bose-Einstein condensates).
Chemical Reactions and Equations
When a chemical species is transformed into another chemical species it is said to have undergone a chemical reaction. It consists of breaking existing bonds and forming new bonds by changing the position of electrons. These reactions are best explained using a chemical equation.
4 Chemistry is the science of the structure and interactions of matter. The INCORRECT alternative is: D)
- All living and nonliving things consist of matter, which is anything that occupies space and has mass.
- Mass is the amount of matter in any object, which does not change.
- Weight, the force of gravity acting on matter, does change.
- When objects are farther from Earth, the pull of gravity is strong; this is why the weight of an astronaut is close to zero in outer space.
5. Structure of Atoms: each element is made up of atoms, the smallest units of matter that retain the properties and characteristics of the element. Is CORRECT to affirm that: B)
- One subatomic particle composed of individual atoms.
- Only three types of subatomic particles are important for understanding the
chemical reactions in the human body: protons, neutrons, and electrons. The dense central core of an atom is its nucleus. - Within the nucleus are positively charged neutrons (p+) and uncharged (neutral) protons (no).
- The tiny, positively charged electrons (e−) move about in a large space surrounding the nucleus.
6. Select the CORRECT alternative: B)
- The
atomic number of an atom is the sum of its protons and neutrons. Because sodium has 11 protons and 12 neutrons, its mass number is 23. - The decay of a radioisotope may be as fast as a fraction of a second or as slow as millions of years. The half-life of an isotope is the time required for half of the radioactive atoms in a sample of that isotope to decay into a more stable form.
- Isotopes are atoms of an element that have similar numbers of neutrons and therefore different mass numbers.
- Certain isotopes called radioactive isotopes (radioisotopes) are stable; their nuclei decay (spontaneously change) into a stable configuration.
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